Signaling system



April 2, 1940. c. E.'LOMAX El AL SIGNALING SYSTEM Filed May 4, 1939 4Sheets-Sheet 1 m RS $5 we? ol b QM m E v H. E E .TLIQWVI b3 1 E 85 NSENE 9Q .eafiw MQQ 9 i I NEW 3Q Si s mg J r 2 37L EFL 7g EG N3 fiS fi e35r Q96 $1 Q13 w 3Q TSB 96 W9 INVENTOR. CLARENCE E LOMAX BY CHARLESF.FFOLLIOTT ATTORNEYS.

p 1940 c. E. LOMAX ET AL SIGNALING SYSTEM Filed May 4, 1939 4Sheets-Sheet 4' CHARLES F. FFOLLIOTT ,nfiw m M ATTORNEYS.

Patented Apr. 2, 1940 PATENT oFFic-E- SIGNALING SYSTEM Clarence E.Lomax, Oak Park, and Charles F. v Ffolliott, Wheaton,'lll., assignors toAssociated Electric Laboratories, Inc., Chicago, 11]., a corporation ofDelaware ApplieationMay 4, 1939,Serial No. 271,696

12 Claims. (01.179-5) The present invention relates to signaling systemand, more particularly, to improvements in combination alarm andtelephone systems of the general character disclosed in Ffolliott PatentNo. 2,122,460,,granted July 5, 1938. s I

In a signaling system of this type, a number of combination alarm andtelephone stations are associated with an operator position by a numberof lines respectively extending therebetween. Telephoneapparatus isprovided at each of the stations and answering apparatus is provided atthe-operator position inorder to facilitate the establishment ofconnections between the stations and the operator position. Furthermore,appa ratus is provided at each of the stations which is selectivelyoperative "to initiate a telephone call or an alarm on the lineextending to thestation, whereupon corresponding signals identifyingtheline and the telephone call or alarm initiated thereon are transmittedto the operator position. Also, alarm recording equipment is usuallyprovided at the operator position which is operative automatically torecord. the code of a line having an alarm thereon, thereby "to identifythe line.

It is an object of the present invention to-provide, ina signalingsystem of the general character just described,- improved andexceedingly simple apparatus for establishing connectionsbetween thecombination alarm and telephonestations and the operator position.

Another, objectof the invention is to provide, in a signaling system ofthe type described, an improved and exceedingly simple arrangementfor-initiating telephone calls and alarms on the combination alarm andtelephone lines 'and'for controlling the transmission of correspondingsignals to the operator position. r s A further object of theinventionis m provide, in a signaling system of the type described an improvedand exceedingly simple arrangement for recording the .code of a linehaving an alarm thereon, thereby to identify the line.

A further object of the invention is to provide, in a signalinglsystemof the type described, an improved correcting circuit adapted to beutilized in conjunction with a line having a ground fault thereon, inorder torender the line usable not withstanding the ground faultthereon, and which embodies, an arrangement for controlling thetransmission' of corresponding signals to the operator position whentelephone calls and alarms are initiated on the associated line.The'features of the present invention are illustrated as beingincorporated in a signaling system including a number of combinationalarm and telephone stations, an operator position and a number of linesrespectively extendingbetween -the stations and the operator position.Telephone apparatus is provided at each of the stations; and answeringapparatus is provided'at the associated with each of the lines; and theline conductors of each of the lines are connected to a source ofcurrent.

Inpacco'rdance with one feature of the invention, an enclosing casinghaving a door is provided at each of the stations; and the telephone,

apparatusat the station is housed in the enclosing casing. The telephoneapparatus comprises a repeater provided with first and second windings;a first telephone instrument of the sound powered type and operativelyassociated with the reduce the effective resistance of the resistor,

thereby effectively to energize the second winding of the repeaterin-order to initiate a telephone call V on the line. 'the station whichis operative to interrupt the Also, a second switch is provided at line,thereby to initiate an alarm on the line. Finally a hookswitch isprovided at the station which is operative to short-circuit the secondwinding of the repeaterand operatively to associate the second telephoneinstrument with the a line.

In accordance with another feature of the invention, each of the linecircuits comprises a control arrangement includingfirst and second,

relays, the first and second relays and the resistor at the associatedstation being connected in series circuit relationship with thecorresponding line. The first and second relays are so connected andarrangedthat the first 'relayiis normally operated and the second relayis normally restored, the second relay being operated when the effectiveresistance of the resistor at the associated station is reduced, and thefirst relay being restored when the line is interrupted, A signalingarrangement is associated with the line circult which is responsive tothe restoration of. the first relay or'the operation of the'second relayfor transmitting a first signal to the operator position,andresponsiveto the restoration of the first relay following theoperation of the second relay for transmitting a second signal to theoperator position, Also, it is noted that the controlarrangementprovided in the line circuit is responsive. to the presence of an alarmon the corresponding line when the line circuit is associated therewithfor controlling thealarm recording equipment, thereby to cause the lineto be identified. v

operator position. A line circuit is individually In accordance with afurther feature of the invention, a correcting circuit is provided whichis adapted to be associated with any one of the lines having a groundfault thereon, thereby to render the faulty line usable notwithstanding,

the ground fault thereon. Also, means is provided which is controlledfrom the operator position for disassociating the corresponding linecircuit from the faulty line and for associating the correcting circuittherewith. Furthermore, a control arrangement is provided in thecorrecting circuit which is responsive to the presence of a telephonecall on the faulty line when the correcting circuit is associatedtherewith for transmitting a first signal to the operator position, andresponsive to the presence of an alarm on the faulty line when thecorrecting circuit is associated therewith for transmitting a secondsignal to the operator position. Also, it is noted that the controlarrangement provided in the correcting circuit is responsive to thepresence of an alarm on the faulty line when the correcting circuit isassociated therewith for controlling the alarm recording equipment,thereby to cause the line to be identified.

Further features of the invention pertain to the particular arrangementof the circuit elements thereof, whereby the above-outlined andadditional features are attained.

The novel features believed to be characteristic of the invention areset forth with particularity in the appended claims. The invention, bothas to its organization and method of operation, together with furtherobjectsand advantages thereof, will best be understood by reference tothe following specification taken in connection with the accompanyingdrawings, in which Figures 1 to 4, inclusive, taken together, illustratediagrammatically the details of a signaling system embodying the presentinvention.

Referring now more particularly to Figs. 1 to 4, inclusive, of thedrawings, the signaling system there illustrated comprises a centraloflice provided with an operator position 00 of the manual type, anumber of combination alarm" and telephone stations including thestation '50, and a number of telephone substations, including thesubstation C. Each of the combination alarm and telephone stations isconnected to the central office by a combination alarm and telephoneline extending therebetween and terminates .in a corresponding jack atthe operator position 60, the combination alarm and telephone station 50being connected to the central oiiice by the line I00 extendingtherebetween and terminating in the jack J I20 at the operator position60. Similarly, each of the telephone substations is "connected to thecentral oflice by a telephone line extending therebetween andterminating in a central ofiice by the line 450 extending .therebctweenand terminating in the jack M at the operator position 60. Morespecifically, the central office may have an ultimate capacity ofseveral thousand combination alarm and telephone lines and severalhundred telephone lines, the combination alarm and telephone lines beingarranged in groups of 200 lines each. A line circuit is individuallyassociated with each of the combination alarm and telephone lines, theline circuit I80 shown in Fig. 1 being individually associated with theline I00; and a line circuit of any desired type is individuallyassociated with each of the telephone lines, the line circuit MB'bei'nging cords, including the patching cord 23! shown in Fig. 2A, a testcircuit 200 shown in Fig. 2B, and position apparatus 400 shown in Fig.4.

Furthermore, the central ofiice comprises alarm recording equipment 300,shown in Fig. 3, which includes a number of finder switches 30.], 302,303, etc, a finder sequence switch 304, a sender switch 305, a sendersequence switch 306 and -"a recorder -30'I.

The alarm recording equipment 300 is of the type'of that disclosed inClarence E. Lomaxand John H. Voss PatentNo'. 2,121,159, granted June 21,1938, and is connected andarranged ina similar manner. Moreparticularly, each of the finder switches 30!, 302, -etc.,"is ofthe'200' point type and corresponds to an associated group of 200"lines; the finder sequence switch 304 is operative to select one of thefinder switches corresponding to a group of 200 lines including aparticular line having an. alarm thereon; the sender switch 305 isoperative to transmit an impulse code to the recorder 30-!identifyingthe particular line; the recorder 301*is operative to print arecord of the code transmitted thereto; and the sender sequence switch306 is operative to control the number of repetitions of the codetransmitted and thereafter to release the alarm recording equipment 300.

Preferably, "the apparatus provided at each combination alarm andtelephone station is identical to that provided atthe station whichcomprises a telephone instrument A of the common battery type, atelephone instrument B of the magnetic or sound powered type, a ringer,

not shown, a repeater I05, a hookswitch SHO, an alarm fswitch Sll5; anda door switch S113. It is noted that this apparatus at the combinationalarm and telephone station 50 is hous'ed in a suitable enclosing easingindicated at 5| which is provided'with a pivotally mounted door 52operatively associated with the door switch S1 IS in a manner more fullydescribed subsequently. Further, it is noted that the telephoneinstrument A comprises a transmitter and a receiver, the receivercooperating with the hookswitch 8H0; while the telephoneinstrument 13comprises a single transmitter and receiver unit. Furthermore, each ofthe telephone substations is provided with apparatus including atelephone instrument of the common battery type and a ringer.

Preferably, each of the line circuits individually associated with thecombination alarm and telephone lines is identical to the line circuit180 individually associated "with the line I 00 "which comprises a linerelay R140, *an'impulse relay R145, an answer relay Rl30, and a numberof control relays RI-50, RIBO, R185 and Rl90. Furthermore, it is notedthat the line circuit I80 controls a supervisory 'lamp L114 associatedwith the jack -J 120 at the operator position 60.

Preferably, each of the patching cords is identical to the patching cord-23| and each of the correcting circuits is identical to the correctingc'ircuit 245. The patching cord 23l comprises two plugs P235 and P240connected together by three conductors C232, C233 and C234; while thecorrectingci-rcuit 245 comprises two jacks U246 and J 251, and a numberof control relays R260, R205, R210, R2715, R280 and R290. Also, asupervisory lamp L2-5G'arrangedat the operator position 80 isindividually associated with-the correcting circuit 245.

The test circuit 200 comprises an ammeter 206, a plug P20I and a numberof keys K201, K2 I0 and K2I5, and it is utilized to test thecombinationalarm and telephone lines for open circuit, short circuit andground circuit faults there'- on in a manner more fully'desoribedsubsequently.

The operator position apparatus 400 arranged at the operator position 00comprises a receiver 453, a transmitter 454, a receiver amplifier 415, atransmitter amplifier 410, a number of repeaters M0, 400 and 485, and acord circuit including two plugs P405 and P440, two ringing keys K405and K430, and two battery supply relays R426 and R421. Further, theoperator position apparatus 400 comprises two keys K4 I5 and K420, asuper-' visory lamp L4I9,an audible alarm 444, and a number of controlrelays R435, R455, R458, R460, R465, R410 and R480.

A better understanding of the connection and arrangement of theapparatus incorporated in the signaling system'will be facilitated froma consideration of the operation thereof incident to the initiation oftelephone calls and alarms at the combination alarm and telephonestations. 4

The line circuit individually associated with each of the combinationalarm and telephone lines is normally partially operated; For example,in the line circuit I individually associated with the combination alarmand telephone line I00 the impulse relay RI45 is normally operated Whilethe line relay RI40 is normally energized but in a restored position,due to the fact that the last-mentioned relay is of the marginal type.The circuit for energizing the windings of the line and impulse relaysRI40 and RI45, respectively, extends from ground by way of the upperwinding of RI45, CI'I5, the contacts IBI, the line conductor CIOI of theline I00, the contact II2 of the vhoo-kswitch SI I0, the winding I01 ofthe repeater I05, the resistor I08, the contacts H6 of the alarm switchSI l5, the line conductor CI02 of the line I00, the contacts I32, thewinding of RI 40 and the lower winding of RI45 to battery. As previouslynoted, the impulse relay RI45 is normally operated, thereby to retaininterrupted at the contacts I46 a circuit, traced hereinafter, forenergizing the winding of the control relay Rltli; and theline relay,RI40 is not operated due to the high series resistance of theabove-traced circuit, the resistance of this circuit residingprincipally in the resistor I08.

In order to initiate a telephone call at one of the combination alarmand telephone stations,it is only necessary to open the door of theenclosing casing thereat. For example, in order to initiate a telephonecall at the combination alarm and telephone station 50,, the door 52 ofthe enclosing casing 55 thereat is opened, thereby to cause the doorswitch SI I3 tobe operated. More particularly, the contacts II4 of thedoor switch S1 I3 are operated into engagement, thereby, to complete anobvious path for short-circuiting the resistor I00. When the resistorI08 is thus shortcircuited, the resistance of the previously tracedseries circuit for energizing the winding of the line relay Rl40 issubstantially reduced, thereby to cause the current traversing thiscircuit to be of the slow-to-operate type. Upon; operating, the

line relay RI40 completes, at the contacts 'I4I,

' an obvious circuit for energizing the winding of the control relayRl50, thereby to cause the latter relay to operate. Upon operating, therelay Rl50oompletes, at the contacts I5I, a holding circuit forenergizing the winding thereof, this" circuit extending from ground byway of the contacts I34, the contacts NH, and the winding of RI50 tobattery. Also, upon operating, the relay R450 prepares at the contactsI52 a further point in thepreviously "mentioned circuit for energizingthe winding of the control relay RI60, interrupts at the'contacts I53 apoint in a circuit, traced hereinafter, for illuminating the lamp LI'Massociated with the jack J I20 at the operator position 60, andcompletes at the contacts I54 an alternative circuit for illuminatingthe supervisory lamp M24. The last-mentioned circuit extends from groundby way of the contacts I54,

the contacts It? and the lamp LI'I4 to battery.

The steady illumination of the supervisory lamp LI I4 associated withthe jack J I 20 at the operator position 00 indicates to the operatorthereatthat a telephone call has been initiated on'thecombination alarmand telephone line I00 extending to the combination alarm and telephonestation 50 andjterminated by the jack J I20. The call on the lineIilllis answered by the operator at the'operator position 50uponinserting the plug P40I of the cord circuit included in the operatorpositionapparatus 400 into the'jack J I20 and upon-operating the keyK420 to its ofi-normal position. When the plugP40I is inserted into theper "terminal of the winding'l0'lor' the repeater I05 by way of thecontacts I I2 of the hookswitch SIIO, CIlli', the'jacktip I2I, theplug'tip 402,

the contacts 406 of the ringing key K405, the

contacts 42I of the key K420, the winding 4I2 of the repeater 4 I 0, thecondenser 4N, the wind-,

ing .4I4 of the repeater M0, the contacts 422 of the key K420, thecontacts 400 of the ringing key K405, the plug ring 403, the jack ringI22, CI02, the contacts N5 of the alarm switch SI I5 thelower terminalof the winding I01. At this time the windings I06 and lii'I of therepeater I05 are operatively coupled and the Windings4l2, 4I4and4IIofthe repeater 450 are operatively coupled, the winding E00 of therepeater I05 beand the contacts I I4'of the door switch SI I3 to ingincluded in an obvious operating circuit for the telephone instrument'B,and the winding 4| I of the repeater M0 being included in an inputcircuit for the receiver amplifier 475. The input circuit for thereceiver amplifier 4'35 extends from one terminal of theamplifier 415 byway of the contacts 4'II, the contacts 40!, the winding 4H of therepeater 450, the contacts 404 and the contacts 413 to the otherterminal of the amplifier 415. The receiver 453 at the operator position60 is included in the output circuit of the receiver amplifier 4'55,this circuit extending from one terminal of the amplifier 4'55 by way ofthe contacts 40L the jack J4'I5, the plug P410, the receiver 453, theplug P4l6, the jack J4'l5 and the contacts 483 to the other terminal ofthe amplifier 415.

Also, when the key K420 is operated away from its normal position, theinput circuit of the transvmitter amplifier 4'56 is completed, thiscircuit extending from ground by way of the contacts 423 of the key K420and the contacts 487 to one ter- 1 minal of the amplifier 416 and fromthe other terminal of the amplifier 416 by wayof the contacts 485, thejack J411, the plug P418, the transmitter 454, the plug P418, the jackJ411, and the winding of R458 to battery. The output circuit of thetransmitter amplifier 416 includes the windings 492 and 494 of therepeater 496 and extends from one terminal of the amplifier 416 by wayof the windings 492 and 494 to the other terminal of the amplifier 416.At this time, the telephone instrument B at the combination alarm andtelephone station 56 is operatively associated with the receiver 453 atthe operator position 66 and signal currents induced in the telephoneinstrurnent B when the party thereat speaks into the telephoneinstrument B will be transmitted to the receiver amplifier 415 and thereamplified and conducted to the receiver 453.

When the operator at the operator position i 66 speaks into thetransmitter 454, undulating signal currents traverse an alternative pathincluded in the input circuit of the transmitter amplifier 416, thispath extending from one terminal of the amplifier 416 by way of thecontacts 481, the condenser 415, the jack J411, the

plug P418, the transmitter 454, the plug P418, the jack J411, and thecontacts 485 to the other terminal of the amplifier 416. The undulatingsignal currents traversing the input circuit of the transmitteramplifier 416 are amplified and transmitted over the output circuitthereof, thereby to cause undulating voltages to be induced in thewinding 493 of the repeater 496 operatively coupled with the winding 494thereof included in the output circuit of the transmitter amplifier 416.The undulating voltages generated in the winding 493 of the repeater 496cause undulating currents to fiow in the circuit of the full-waverectifier network 461 in an obvious manner, thereby to cause a full-waverectifier current to traverse the winding of the control relay R465 inan obvious manner. When thus energized, the relay R465 operates tocomplete at the contacts 466 an obvious circuit for energizing thecontrol relay R466, thereby to cause the latter relay to operate. Uponoperating, the relay R466 interrupts at the contacts 46! and at thecontacts 464 points in the previously traced circuit for connecting thewinding 4 of the re peater M6 in the input circuit of the receiveramplifier 415 and completes at the contacts 462 and at the contacts 463a circuit for connecting the winding 4 of the repeater M6 to the winding49I of the repeater 496. The last-mentioned circuit extends from theupper terminal ofthe winding 4 II byway of the contacts 462, the winding49I and the contacts 463 to the lower terminal of the winding 4! I. Atthis time the windings 49I and 492 of the repeater 496 are operativelycoupled, thereby to cause the amplified undulating currents to beinduced in the winding 49I of the repeater 496.

Each time the operator at the operator position 66 speaks into thetransmitter 454, the control relay R466 operates in the above-describedmanner, thereby operatively to connect the winding M I of the repeaterM6 to the winding 49I of the repeater 496 in order to cause signalcurrents to be transmitted from the transmitter 454 to the telephoneinstrument B in an obvious manner. Each time the operator at theoperator position 66 listens, the control relay R466 recurrentsto betransmitted from the telephone 1114 strument B to the receiver 453 in anobvious manner.

, It is contemplated that the party at the combination alarm andtelephone station 56 will utilize the sound powered telephone instrumentB thereat in conversing with the operator at the operator position 66.However, the party at the station 56 may utilize the common batterytelephone instrument A at the station 56. In any case, the commonbattery telephone instrument A is utilized by the party at the station56 when the call is to be extended by the operator at the operatorposition 66 over a telephone line in a manner more fully describedhereinafter. Assuming that the party at the combination alarm andtelephone station 56 removes the receiver of the telephone instrument Afrom its switchhook, the hookswitch SI I6 is operated, thereby tointerrupt at the contacts -I I2 thereof a point in the previously tracedpath for connecting the winding I61 of the repeater I65 to theline-conductors C I DI and C I 62 of the line I66 and to complete at thecontacts III thereof a path for connecting the telephone instrument Aacross the line conductors C'I6l and CI62 of the line I66. Thelast-mentioned path extends from the line conductor CI6I by way of CI63,the telephone instrument A, CI64, the contacts I I I of the hookswitchSI I6, and the contacts H6 of the alarm switch SI I to the lineconductor CI62. At this time, talking battery is supplied tothetelephone instrument A from the impulse relay RI included-in the linecircuit I86, ground potential being connected to the line conductor CI6Iand battery potential being connected to the line conductor CI62 by wayof the windings of the impulse relay RI45 and the line relay RI46 aspreviously explained. Although a very feeble current traverses thetelephone instrument A by wayof the windings of the impulse relay RI45and the line relay RI46, sufiicient current traverses the telephoneinstrument A to control the receiver amplifier 415. Thus, the telephoneine strument A at the. combination alarm and telephone station 56 may beutilized to converse with the operator at the operator position 66.

A call which is to be extended from one of the combination alarm andtelephone stations, such, for example, as the station 56, to one of thetelephone substations, such, for example, as the substation C, is firstinitiated at the combination alarm and telephone station 56- andanswered at the operator position 66 in the previously described manner,the telephone instrument B being utilized at the station 56 to conversewith the operator at the operator position 66. The operator at theoperator position 66 then advises the party at the combination alarm andtelephone station 56 to remove the receiver of the telephone instrumentA thereat from its switchhook, thereby to cause the telephone instrumentA to be connected-across the line conductors CHM and CI62 of thecombination alarm and telephone line I66 in the previously describedmanner. The operator at the operator position 66 then actuates the keyK4 I5 thereby to complete at the contacts 4I6 thereof a circuit forenergizing the lower winding of the control relay R435, this circuitextending from ground by way of the lower winding of R435, the contacts424 of the key K426 and the contacts MB of the key K4I5 to battery. Whenenergized over the above-traced circuit, the relay R435 operates tocomplete, at the contacts 438, a holding circuit for energizing'theupper winding thereof in series with the winding of the answer relayRI30 in the line circuit- I80 individually associated with the line I00.This circuit extends from ground by way of the upper winding of R435,the contacts 438, the plug sleeve 404, the jack sleeve I23, CH6 and thewinding of RI30 to battery. When energized ,over the above-tracedcircuit, the answer relay RI30 operates to interrupt, at the contactsI34, a point in the previously traced holding circuit for energizing thewinding of the control the winding of R480 to battery. When energizedover the above traced circuit, the relay R400 relay BI50 and completes,atthe contacts I35, an obvious holding circuit for energizing the lower.winding of the impulse relay RI45. Also, the answer relay'Rltilinterrupts, atthe contacts I3i and at the contacts I32, the previouslytraced series circuit for energizing the windings of the line relay R440and the impulse relay RI45, thereby to clear the combination alarm andtelephone line Hill of impedance elements. Further, the answer relayBIZ-i0 completes, at the contacts I33, a circuit for energizing thewinding of the line relay RI40 in a reverse direction, ground by way ofthe contacts 535, the winding of RI40, the contacts I33 and the resistorI I8 to battery. When the above-traced circuit is completed, the linerelay R140 quickly restores and does not reoperate due to the highresistance of the resistor IIB. Upon restoring, theline relay RI40interrupts, at thecontacts MI, the previously traced original circuitfor energizing the vwinding of the control relayRiiW, thereby'toremainder of the relays in the line circuit I00 occupy their restoredpositions at this-time.

Also, upon operating, the control relay R435 completes, at the contacts439, a series circuit for energizing the winding of the relay R455 andfor illuminating the supervisory lamp L4I9, this circuit extending fromground by way of the contacts 439, the contacts 428, the lamp L4 I0, andthe winding of R455 vto battery. When energized over. the above-tracedcircuit, the control relay R455 operates to prepare, at the contacts456, a circuit, traced hereinafter, for operating the alarm 444, Theillumination of the supervisory lamp L4H) gives the operator at theoperator position 00 answer and disconnect supervision in connectionwith the called telephone line in a manner more fully describedhereinafter. Furthermore, the control relay R435 completes at thecontacts 435 a series circuit for energizing the windings of. thecontrol relays R410 and R400, this circuit extending from ground by wayof the contacts'439, the contacts 425 of the key K420, the'winding ofR470 and the relay R480 interrupts at tl'ie conta'cts 48I and 1 at thecontacts 483the connection between the receiver 453 and the outputcircuit of the ref this circuit extending from ceiver amplifier 415,completes at the contacts 482. and at the contacts 484 an operativeconnection between the receiver 453 and the winding 490 of the repeater435, interrupts at the contacts 485and at the contacts 48'! theconnection between the transmitter 454and the input circuit of thetransmitter amplifier 416, and completes at the contacts 4% and at thecontacts 488 an operative connection between the transmitter 454. andthe windings 458 and 499 of the repeater 495. The circuit foroperatively connecting the receiver 453 to the winding 496 of therepeater 495 extends from one terminal of the receiver 453 by way of theplug P415, the jack J4'i5, the contacts 482, the winding 4%, thecondenser 438, the contacts 404, the jack J4I5 and the plug P434 to theother terminal of the receivertriii. The circuit for operativelyconnecting the transmitter 454 to the windings 438 and-499 of therepeater 495 extends from ground by way of the contacts 423 of the keyK420, the contacts 488, the windings 499 and 498, thecon- ,tacts406, thejack J4I'I, theplug P4'I't, the transthe connection between the winding4 of the repeater 4m and the input circuit of the receiver amplifier 445and completes at the contacts'4l2 and at the contacts 474 a connectionbetween the winding 4M of the repeater M0 and thewindings 4% and 49? ofthe repeater 495.

The last-mentioned connection extends from the upper terminal of thewinding of R4 by wayroi the contactsdtt, the contacts 412, the

windings400 and 491, the contacts 414, and the contacts 404 to the lowerterminal of the winding Al I. v

Finally, upon operating, the control relay R435 completes, at thecontacts 430 and 43?, a loop circuit extending between the batterysupply relay R423 and the, telephone instrument A at the combination,alarm and telephone station 50.

This loop circuit extends from ground by wayof the upper winding-ofR426, the contacts 436 and the contacts 406 of the ringing key K405 tothe plug-tip 402and from battery by way of the lower winding of'R lZE,the contacts 431 and the contacts 408 of the ringing key K405 to theplug ring 403, theplug tip 402 and the plug ring 403 being included in acircuit extending to the telephone instrument A at the station 5i aspreviously explained. Thus, atthis time, the common battery telephoneinstrument A at the combination alarm and telephone station 559 isoperatively associated with the receiver 453 and the transmitter 454 atthe operator position 60 by into the jack J445 individually associatedwith the telephone line 450 and then operates the ringing key'K430 awayfrom its normal position,

, thereby to cause ringing current to be projected over the telephoneline 450 to the telephone substation C. The circuit for projectingringing current to the telephone substation C extends from one terminalof a source of alternating curterminal of the source of alternatingcurrent supply by way of the contacts 434 of the ringing key K430, theplug ring 442, the jack ring 441. and the line circuit 449 to, the lineconductor C452 of the telephone line 450, the ringer atv the telephonesubstation C being bridged across the line conductors C454 and C452. Theoperator at the operator position 60 operates the. ringing key hack andforth between its normal and.- 01T- normal positions intermittently.When the party at the telephone substation 0 answers. thecall, a loopcircuit is completed between the telephone instrument thereat and thebattery supply relay R421. when the ringing key K430 is restored to itsnormal position, this loop circuit extending from ground by way of theupper winding of R421 and the contacts 43.! of the ringing key K430 tothe plug tip 44! and from battery byway of the lower winding of R421 andthe contacts 4.33 of the ringing key K430. to. the plug ring 442, theplug tip 44! and the plug ring 442 being included in the loop circuitextending to the telephone sub-F station C as previously explained. Whenthe loop circuit is completed between the telephone instrument at thetelephone substation C and the battery supply relay R421, the windingsof the last-mentioned relay are energized, thereby to.

loop circuit extending between the telephone instrument A at thecombination alarm and telephone station 50 and the battery supply relayR429 and the loop circuit extending between the telephone instrument atthe telephone substation C and the battery supply relay R421 areoperatively connected, the upper windings of the relays R425 and R421being connected together by way of the condenser 4H and the lowerwindings of the relays R426 and R421 being connected to-.

g-ether by way of the condenser H8.

The operator at the operator position 60 may monitor the establishedconnection, between thecombination alarm and telephone station 50 andthe telephone substation C or she may-disconnect from this establishedconnection. Inorder to disconnect from the established connection, the

operator at the operator position 60 restores the keys K415 and K420 totheir normal positions.

When the key K420 is restored to its normal position, the previouslytraced series circuit for energizing the windings of the control relaysR410 and R480 is interrupted at the contacts 425 thereof and thepreviously traced circuit for energizing the winding of the controlrelay R458 is interrupted at the contacts 423 thereof, thereby to causethe last-mentioned relays to restore.

Upon restoring, the control relays R410 and R480 interrupt thepreviously traced connections between the receiver 453 and thetransmitter 454 and the repeater M0 by way of the repeater 495 andcomplete the previously traced connections between the receiver 453 andthe transmitter 454 and the repeater M0 by way of the amplifiers 415 and416. Upon restoring, the control relay R458 prepares at the contacts 459a point in the preares-e27 viously mentioned circuit for operating thealarm 444.

When the conversation between the combination alarm and telephonestation 50 and the telephone substation C is terminated, the partiesthereat. replace the receivers, of the telephone instruments thereatupon their respective switchhooks, thereby to interrupt the previouslytraced loop circuits, extending between the battery supply relays R426and R421 and the telephone instrumentsat the station 50. and at thesubstation C, respectively, in order to cause the battery supply relaysR426 and R421 tov restore. Upon restoring, the relay R421 recompletes atthe contacts 428 the previously traced series circuit for illuminatingthe supervisory lamp L419 and for energizing the Winding of the controlrelay R455, thereby to. cause the last-mentioned relay to operate. Uponoperating, the relay R455 come pletes, at the contacts 450, thepreviously mentioned circuit for operating the alarm 444, this circuitextending from ground by way of the contacts 459, the contacts 456 andthe winding of the alarm 444 to battery. The illumination of the.supervisory lamp L419 and the operation of the alarm 444 indicate to theoperator at the operator positionfifl that the party at the telephonesubstation C has replaced the receiver of the telephone instrumentthereat upon its switchhook.

The operator at the operator position 60 may arrest the operation of thealarm 444 by reoperating the key K420 away from its normal position,thereby to complete the previously traced circuits for energizing thewindings of the control relays R410, R480 and R458 in order to cause thelast-mentioned relays to operate. Upon operating, the control relay R458interrupts, at the contacts 459, the previously traced circuit foroperating the alarm 444 and, upon operating, the control relays R410 andR480 complete the previously traced circuits for operative- 1yconnecting the receiver 453 and the transmitter 454 to the: repeater 410by way of the repeater 495 as previously explained. At this time, theoperator at the operator position 60 may again converse with the partyat the combination alarm and telephone station 50 in the event he hasnot replaced the receiver of the telephone instrument A thereat upon itsswitchhook.

In the event the operator at the operator position 60 wishesto reringthe combination alarmand telephone station 50- in case the party thereathas replaced the receiver of the telephone instrument A upon itsswitchhook, the ringing key K405 is intermittently operated back andforth between its normal and off-normal positions. When the ringingkeyK405 is operated to its off-normal position, a circuit is completed forprojecting ringing current over the line N19 to the combination alarmand telephone station 50, this circuit extending from one terminal of asuitable source of alternating current supply by Way of the contacts401' of the ringing key K405, to the plug tip 402 and from the otherterminal of the source of alternating current BO-L supply by way of thecontacts 409 of the ringing key K405 to the plug ring 403, the plugtip402 and the plug ring 403 being included in a circuit extending byway of theline [00 to the combination alarm and telephone station 50.The alternating current thus projected, over the line I00 to the station50 causes the ringer thereat to be actuated in the event the receiver ofthe telephone instmmentA has been replaced upon its switchhook in theusual manner. I

In order competely to release the established connection between thecombination alarm and telephone station 50 and the telephone substationC, the operator at the operator position '55 withdraws the plugs P ltland P440 from the jacks J I20 and J445, respectively terminating thelines Hill and 153. When the plug 462 is withdrawn from the jack J 23,the previously tracedcircuit for energizing in series the upper windingof the ,for energizing the winding of the control relay R455 in order tocause the supervisoryflamp to be extinguished and the relay R455 torestore. Upon restoring, the answer relay 'RI3Il interrupts at thecontacts 135 the previously traced'alternative circuits for energizingthe lowerwinding of the impulse relay R145, prepares atthe con- .tactsI34 a point in the previously traced holding circuit forenergizingthewinding of the control relay RI 555 and completes at the contacts.I3I and at the contacts I32 the previously traced-circuit forenergizing the windings of the impulse relay RME in series with thewinding of the line relay RIM. The. impulse relay RI IE remains in itsoperated positionat this time. However, the line relay RIM remainsrestored, due to the high series resistance of the circuit forenergizingthe winding thereof,.assuming that the partyat the combination alarm andtelephone station 59 has closed the door 52 of the enclosing casing 5Ithereat, thereby to operate the door switch SI I3 in order to interruptat the contacts I I4 thereof:

the previously mentioned path for short-circuiting the resistor I08 aspreviously explained.-

In order to initiate an alarm on one of the combination alarm andtelephone lines, the door of the enclosing casing at the associatedstation is opened and then the alarm switch thereat is operated.For'example, in order to initiate an alarm on the combination alarm andtelephone line I60, theparty atthe combination alarm and telephonestation 55 opens the door 52 of the enclosing casing 5i thereat,*therebyto cause the door switchSiIS to be operated in order to complete at-thecontacts I'M thereof the previously mentioned path for short-circuitingthe resistor I08. When the resistor i 38 is thus shortcircuited, theline'relay, RIM] and the control relay RI50 in the line circuit I89individually associated with-the combination alarm and telephone line itoperate'as previously explained, thereby to initiate a telephone calljonthe line I and to cause the supervisory lamp LI 'M associated with thejack J I283 at the operator position 60 to be steadily illuminated. Theparty at the station 50 then operates. the alarm switch SII momentarily,thereby to-interrupt at the contacts H6 thereof the previously tracedseries circuit for energizing the winding of the line relay RIM and thewindings of the-impulse relay RI45; Also, at the contacts II! of thealarm switch SI I5, there is completed a path for short-cir- ;cuitingthe upper winding'of the impulse relay.

am, this path extendin from ground by way of the contacts I ll of thealarm switch SI.I5, the

contacts ,I I4 of the door switch SI I3, the winding Iil'lof therepeater I05, the contacts I I2 of the hookswitch SIII], Gilli, thecontacts I3 I, CH5 and the upper winding of RIM to'ground. When theabove-traced series circuit for energizing the windings of the impulserelay. RI45 is interrupted and the previously traced path forshort-circuiting the upper winding of the impulse relay RME iscompleted, the impulse relay RI45 immediately restoresv to complete atthe of the control relay Rliiii, this circuit extending from ground byway of the contacts I46, the

. contacts I46 a circuit for energizing the'winding 7 contacts I52, thewinding of Rififi' anoLthe resistor I24 to battery. When energizedl overthe above-traced circuit, the relay RISE operates to complete at thecontacts I6I an. obvious holding circuit forenergizing the windingthereof inserieswith the resistor I24. It is noted that the alarm switchSI I5 at the combination alarm andoperates and the line relay RIMoperates in the I event that it has restored, the control relay RI 50remaining operated due to the completed holding circuit for energizingthe winding thereof. Upon. reoperating, the impulse relay RI45interrupts at the contacts I45 a point in the previously traced 5original circuit for energizing the winding of'the.

, phone line IIIII by operating'the alarm switch SII5 regardless ofwhether the receiver of the telephone instrument A at the station 5t hasbeen removed from its switchhook; In the event the, receiver of thetelephone instrument A at the station 50 has been removed from itsswitchhook, operation of the alarm switch. SI I5 completes; at thecontacts I" thereof, an alternative path for short-circuiting the upperwinding of the impulse relay RI45, this circuitextending" from groundat.the contacts II! of the alarm switch SI I5, the

contacts III of thehookswitch'slm, CIM, the telephone instrumentA,'CI03, C'II] I,'the contacts I3I, CH5 and the upper winding of theimpulse relay RI to ground. Thus, the control relay,

RIBO is operated incident to the operation ofthe alarm switch SI I 5regardless of whether the tele phone instrument B or the telephoneinstrument A is employed at the station to converse with the operator atthe operator position 60.

Also, upon operating, the control relay RIBII interrupts at the contactsI63 the previously. traced circuit for illuminating'steadily the super:

visory lamp LIH associated with the jackJI2B at the operator positionand completes at the contacts I62 a circuit for illuminatingintermittently the supervisory lamp LI I4. The last-mentioned circuitextends from interrupted ground potential appearing'upon the controlconductor CHO byway of the contacts I62 and the lampv LI I4 to'batte'ry.The flashing of the supervisory lamp LI'I4 associated withthe jack J I20at the operator position 60 indicates to the operator thereat that analarm conditionis present upon 40? control conductor CI'I3.'

the combination alarm and telephone line I00. Accordingly, the operatorat the operator position 60 answers the call on the line I immediatelyand in preference to other ordinary telephone calls Waiting to beanswered. The mode of answering the alarm call on'the line I00 at theoperator position 60 is the same as that previously, explained. Afterthe call has been answered at the operator position 60, the operatorthereat may learn from the party at the comthe combination alarm andtelephone line I00 completes at the contacts H54 and at the contacts I65obvious paths for applying ground potential tothe start conductor CH2and to the control conductor CI'II respectively. The application ofground potential to the start conductor CH2 and to the control conductorCI'lI initiates the operation of the finder sequence switch 304, therebyto cause the finder sequence switch 304 to select the particular finderswitch 30I associated with the group or" 200 lines including the lineI00 having the alarm condition thereon. Subsequently,the selected finderswitch 3M operates to. select the line I00 in the associated group of200 lines having the alarm condition thereon, whereupon the senderswitch 3&5 operates to cause the recorder 30? to operate and make arecord of the particular line I00 having the alarm condition thereon,thereby to identify the lastmentioned line. The sender sequence switch306 causes the sender switch 305 to transmit the code to the recorder301 a number of times; and thereafter thealarm recording equipment 300is released and ground potential is applied to the The application ofground potential to the control conductor CH3 completes a path forshortcircuiting the winding of the control relay R160 inthe line circuitI80 individually associated with the combination al'armandtelepho'neline I00."

This path extendsfrom the grounded control conductor Cl'l3'tofthe upperterminal of the winding of the relay RIM, the lower terminal of thewinding of the relay RIM! having ground potential connected thereto aspreviously noted.

When the winding of the control relay RI60 is thus short-circuited, thisrelay restores'tointerrupt at the contacts I 6! a further point in thepreviously traced holding circuit for energizing the winding thereof, tointerrupt at the contacts I62 the previously traced circuit forintermittently illuminating the supervisory lamp LI'M associated withthe jack J I20 at the operator position 00, to prepare at the contactsI63 2. point in the previously traced circuit for steadily illuminatingthe supervisorylampLIM, and to inter-" rupt, at the contacts I64 and atthe contacts I65, respectively, the previously mentioned paths forapplying ground potential to the start conductor CI12and to the controlconductor CHI. At this time, the line circuit I30 individuallyassociated with the combination alarm and telephone line I00 occupiesits usually operated position to-mark the line I00 as having a telephonecall thereon. The line relay EH40, the impulse relay EMS and the controlrelay RI 50- occupy their operated positions at this time, aspreviouslynoted.

The line circuit individually associated with each of the combinationalarm and .telepl'u ne= lines is so connected and arranged, that thesupervisory lamp associated with the jack'terminating the line at theoperator position 60 is illuminated in the event a fault appears uponthe line. For example, the line circuit I80 individually associated.with the combination alarm and telephone line I00 is so connected andarranged that the supervisory lamp LI'M associated withthe jack J 5253terminating. the line '00 at the operator position 60 is illuminated inthe event the line I00 has an open circuit, a short circuit, or a groundcircuit fault thereon. More particularly, in the event the lineconductors CHM and CIO-2 of the combination alarm and telephone line I00 are shorted together, an alternative circuit is completed forefiectively energizing the winding of the line relay RI40, this circuitextending from ground by way of the upper winding of the impulse relayRI45, CH5, the contacts I3l, CIOI, the short circuit between CI 0| andCI02, CI02, the contacts I32, the winding of the line relay RI40 andthelower winding of the impulse relay RI45 to battery. When energized overthe above-traced circuit, the line relay RI40 operates to complete atthe contacts I the previously mentioned circuit for energizing thewinding of the control relay RI50, thereby to cause the latter relay tooperate. Upon operating, the control relay RI 50 completes, at thecontacts I5I, the previously traced holding circuit for energizing thewinding thereof, and completes at the contacts I54 the previously tracedcircuit for steadilyilluminating the supervisory lamp LIH associatedwith the jack J I20 at the operator position 60.

Also, in the event either one of the line condoctors CHM and CI02 of thecombination alarm and telephone line I0li is broken, the previouslytraced circuit for energizingin series the upper and lower windingsofthe impulse relay R145 is interrupted, thereby to cause the latterrelay to restore. Upon restoring, the impulse relay Rl lt completes atthe contacts hit an alternative circuit for steadily illuminating thesupervisory lamp LEM associated with the jack J I20 at-the operatorposition til. The last-mentioned circuit extends from ground by way ofthe contacts M6, the cont acts I53, the contacts I83 and the lamp L3!!!to battery.

= rthermore, in the event either the positive line conductor Cllli orthe negative line conductor CI02 of the combination alarm and telephoneline I 0i! is grounded, a circuit is completed for,

effectively energizing the winding of the line relay RMB. Thelast-mentioned circuit extends from battery by way of the lower windingof the impulse relay EH45, the winding of the line relay RMEI' and thecontacts I32 to the line conductor Cl02. In the event the negative lineconductor CW2 is grounded, the last-mentioned circuit is completeddirectly; and,in the event the positive line conductor CI M is grounded,the lastmentioned circuit is completed by way of the contacts 5- of thealarm switch SII5, the resistor I 08, the winding IElTI'of the repeaterI05 and the contacts it?! either hookswitch SI II) to the groundedpositive line conductor CHM. In either event the line relay Rl illoperates, thereby to cause the control relay R150 to operate andcomplete the previouslyxtraced circuit for steadily illuminating thesupervisory lamp LIM associated with the jack J I 20 atthe operatorposition 60 as previously explained.

When the supervisory lamp L'Il i associated with the jack J l20at the.operator position 60 is illuminated; the operator thereat is advised uthat a calling condition is present onthe combination alarm andtelephone line 100, whereupon she inserts the plug P401 of the cordcircuit in the operator position apparatus 400 into the jack J 120 aspreviously explained. Theoperator at the operator position 60 thenoperates the key K420, thereby operatively to associate the receiver ingorder. The line 100 is testedby inserting the plug P201 of the testcircuit 200 into the jack J and then manipulating the keys associatedwith the test circuit 200 in a manner more fully described hereinafter.

When the plug P201 of the test circuit 200 is inserted into the jackJ120, a circuit is completed -forv energizing the winding of the answerrelay R inlthe line circuit 180 individually associated with thecombination alarm and telephone way of the resistor 205, the plug sleeve204, the

jack sleeve 123, G110 and the winding of R130 to battery. When energizedover the abovetraced circuit, the answer relay R130 operates tointerrupt at the contacts 131 andat'the contacts 132 the previouslytraced circuit for energizing in series the winding of the line relay Rand the windings of the impulse relay R145, and completes, at thecontacts 133 and at the contacts 135, the previously traced circuit forenergizing the winding of the line relay R140 in a reverse direction,thereby to cause the lastmentioned relay to restore; Also, the answerrelay R130 completes at the contacts 135 the previously traced holdingcircuit for energizing the lower winding of the impulse relay R145.Accordingly, at this time, the answer relay R130 and the impulse relay Rin the line circuit 180 occupy their operated positions while the linerelay R140 and the control relay R in the line circuit 100 occupy theirrestored positions.

The operator at the operator position'60 checks the operation of theammeter 206 included in the test circuit 200 by operating the key K215away from its normal position in one direction, thereby to complete atthe contacts 223 and at the contacts 225 of the key K215 a test circuitfor the ammeter 200. This test circuit extends from ground by way of thecontacts 225 of the key K215, the winding of the ammeter 206, theresistor 226 and the contacts 223 of the key K215 to battery. Assumingthat the ammeter 206 registers properly, thekey K215 is returned to itsnormal position.

The operator at the operator position 60 then operates the key K20! awayfrom its normal position, thereby to complete a circuit for testing thecondition of the line circuit 180. More particularly, a circuit iscompleted for testing whether or not the line 100 has been freed ofimpedance elements including the winding of the line relay R140 and thelower winding of the impulse relay R145. This test circuit extends fromground by way of the contacts 209 of the key K201, the contacts 2H ofthe key K215, C230, the contacts 221 of the key K215, the contacts 224of the key K215, the winding of the ammeter 206, the resistor 226, thecontacts 222 of the key K215,

the contacts zis' of the key 215, c229,- the contacts 214 of the keyK210, the plug ring 203 and the jack ring 122 to the negative lineconductor C102 of the line 100. In the event the line 100 has been freedof impedance elements including the winding of the line relay R140 andthe lower Winding of the impulse relay R145 due to the proper operationof the answer relay R140, no, potential appearsupon the negative lineconductor 0102. Accordingly, the ammeter 206 does not register anycurrent flowing over the above- I traced circuit. On the other hand, inthe event the negative line conductor 0102 of the line 100 has not beenfreed of impedance elements including the winding of the line relay R140and the lower winding of the impulse relay R145,

I due' to the improper operation of the answer relay R130, batterypotential appears upon the negative line conductor C102 of the line 100,this battery potential being derived at the lower winding'of the impulserelay R145. Accordingly, the ammeter 200 registers a current flowingover the above-traced circuit, thereby to indicate to the operator atthe operator: position 60 that the answer relay R130 in the line circuithas not operated to free the line 100 of impedance elements.

Assuming that the answer relay R130 in the line circuit 100 has operatedproperly as indicated, the operator at the operator position 60 thenrestores .thekey K201 to its normal position'and operates the key K215away from its normal position in the opposite direction, thereby tocomplete at the contacts 216 of the key K215 a path extending fromground by wayof the contacts .216 of the key K215, the contacts 208 ofthe key K201 and the contacts 212 of the key K210 to the-plug tip 202andto complete at the contacts 218 of the key K215 a path extending frombattery by way of the'contacts 218 of the key K215, the contacts 222 ofthe key K215 and the resistor 226 to the negative terminal of theammeter 205. When these paths are completed, the ammeter206 fails toregister any current in the event either of the line conductors C101 andC102 of the line 100 is interrupted. Also, in the event the lineconductors C101 and C102 of the line 100 are shorted together, theammeter206 will register a high value of current. The circuit forcausing theammeter 206 to register a high value of current extends fromground potential appearing on the plug tip 202 by way of the jack tip121, G101, the shorted connection between C101 and C102, C102, thejack-ring 122, the plug ring 203, the contacts 214 of the key K210, thecontacts 220 of the key K215 and the contacts 224 of the key K215 to thepositive terminal of the ammeter 206.

' On the other hand, in the event either of the line conductors C101 andC102 of the line 100 is grounded, the ammeter'206 will read some valueof current flowing over acircuit including the line conductors of theline 100. In the present instance, ground potential is connected by wayof the previously traced path to the plug tip 202 and battery potentialis connected by way of the previously traced path including the ammeter206 to the plug ring 203. Accordingly, at this time, if the positiveline conductor C101 of the line '100 is grounded, the ammeter 206 willregister a low value of current due to the fact that the resistor 108 atthe combination alarm and telephone station 50 is included in thepreviously traced connection between the'line conductors C101 and C102of the line 100. On

the other hand, in the event the negative line conductor C582 of theline 100 is grounded, the ammeter will register a high value of currentdue to the fact that the resistor I08 at the comblnaticn alarm andtelephone station 5!] is excluded from the circuit including the ammeterIn the event the ammeter 206 registers either a high value or a lowvalue of current, the key K258 is operated. Upon operating the key K2til, ground potential is applied to the plug ring and battery potentialis applied to the plug tip The path for applying ground poten-. tial tothe plug ring extends from ground by way of the'contacts 2E6 of the keyK2l5, the contacts 283 of the key K201 C223, and the contacts 2H3 of thekey Ki Ill to the plug ring 293; and the path for applying batterypotential to the plug tip ilii ex-tends from battery by way or thecontacts are of the key K2! 5, the con- 222' of the key KZIE, theresister 226, the winding of the arnrneter 206, the contacts 224 of thekey K2l5, the contacts 220 of the key C227 and the contacts 2H of thekey KQlil to the plug tip 282.

With the key K249 operated, the ammeter 286 will register a high valueof current in the event the positive line conductor CNl of the line I90is grounded, due to the fact that the resistor I03 at th combinationalarm and telephone station is excluded from the path including thewinding of the arnmeter 2%; while the ammeter 266 will register alowvalue of current in the event that the negative line conductor C162 ofthe line lid? is grounded, clue to the fact that the resistor Hit at thecombination alarm and telephone station is included in the pathincluding the winding of the ammeter 2%. From the above, it w l beunderstood that, by operating the key Kfilli back and forth while thekey K2I5 is operated in the opposite direction away from its normalposition, the particular one of the line conductors Gilli or (H92 of theline N30 which is grounded may be determined by the operator at theoperator position 60.

Assuming that one of the line conductors OH]! or Gilli. of thecombination alarm and telephone line lfifi is grounded, the operator atthe operator position fill first determines which one of the lineconductors is grounded and then establishes a connection between thedefective line H10 and one of the correcting circuits, such, forexample, as the correcting circuit 245, by utilizing one of the patchingcords, such, for example, as the, patching cord 23L First, theoperatorat the operator position to inserts the plug P235 of the patching cord2M into the jack J I29 and then inserts the plug 1 2% of the patchingcord 23! into on of the jacks J 2418 or J 25! of the correct-- circuitM5 depending upon which one of the line conductors of the combinationalarm and telephone line tilt is grounded. In the event the positiveline conductor CH3! of the line I00 is grounded, the plug 2% of thepatching cord 23! is inserted into the jack J25l. On the other .hand, inthe event the negative line conductor Cltfi of the line llll isgrounded, the plug 248 of the patching cord 235i is inserted into thejack J 2%.

Assuming that the negative line conductor CW2 .oi' the combination alarmand telephone line M8 is grounded, the plugs P235 and PZM] of theypatching cord 23?! are inserted into the jacks J i and JZM,respectively. When the plug P245) is inserted into the jack J 246, anobvious path is completed at'the contacts 258 of the jackJZdfi forenergizing the winding of the control relay R255, thereby to cause thelatter relay to operate. Also, when the plug PEdfl. is inserted into thejack JZAB, a circuit is completed for energizing thev winding of theanswer relay EH36 in the line circuit l8ll individually associated withthe combination alarm and telephone line Hill. The last-mentionedcircuit extends from ground by way of the contacts 285, the resistor 2M,C292, the jack sleeve 249, the plug sleeve t ll, C232, the plug sleeve2.36, the jack sleeve l23, CH5 and the winding of RI to battery. Vfhenenergized over the above-traced circuit, the answer relay Rite operatesas previously explained, thereby to cause the impulse relay Rl lfi toremain in its operated position and the line relay Rl lll to restore.Upon restoring, the line relay Rldllinterrupts the previously tracedcircuit for energizing the winding of the control relay Rifill in theevent the lastmentioned relay is operated. Accordingly, at this time thecircuit for steadily illuminating the lamp LIM associated with the jackJ l2d at the operator position is interrupted. Finally. when the plugP240 is inserted into the' jack J 2%, a circuit is completed forenergizing the. winding of the control relay R21 B in the correctingcircuit 265, this circuit extending from ground by way of the jack'ring248, the plug ring 2 52, C233, the plug ring 237, the jack ring I22,CIGZ, the contacts MS of the alarm switch SH the resistor use, thewinding ll of the repeater let, the contacts H2 of the hookswitch Sllll,cm, the jack tip till, the plug tip 238, G235, the plug tip M3, thejacktip 24?, the contacts 262, the contacts 166, the

contacts 2'57 and the winding of Bill? to battery.

It is noted'that direct ground potential at the jack ring M8 is appliedto the grounded negative line conductor CW2 of the line iii!) and thatthe above-traced circuit for energizing the winding of the control relayR279 in the correcting circuit 245 includes the resistor its.Accordingly, the control relay R2!!! in the correcting circuit 245 doesnot operate at this time due to the high series resistance of thecircuit for energizing 1c windingthereof.

At this time, the defective combination alarm and telephone line Hillhas been operative by utilizing the correcting circuit 2&5, whichcircuit is utilized in connection with the line lliil until thenegativeline conductor C95 2 of the line Hill is cleared of the grounding faultthereon.

At this time a telephone call may be initiated on the line lllfl in theusual manner by opening the door 52 of the enclosing casing El at thecombination alarm and telephone station Ell as previously explained,thereby to complete at the contacts H4 of the door switch S1 l3 thepreviously mentioned pathfor short-circuiting the resistor I08. When theresistor M8 is thus short-circuitecl, the resistance of the previouslytraced circuit for energizing the winding of the control relay R210 isappreciably reduced, thereby to cause the lastmentioned relay to beeffectively energized,

ing the-winding thereof by way of the grounded control conductor C233,prepares at the contacts 216 a further point in the previously mentionedcircuit for energizing the winding of the control relay R280 andinterrupts at the contacts 211 an obvious path for short-circuiting theresistor 213,

. 'ing the winding of the control relay R210.

thereby to cause the resistor 213 to be inserted in series in thepreviously'traced circuit for energiz- When the resistor 213 is insertedinto the circuit for energizing the winding of the control relay R210,the last-mentioned relay remains in its operated condition. However, itis rendered extremely fast to restore in the event the circuit forenergizing the winding thereof is momentarily interrupted. Also, uponoperating, the control relay R215 completes at the contacts 218 acircuit for steadily illuminating the supervisory lamp L250 individuallyassociated with the connecting circuit 245, this circuit extending fromground by way of the contacts 284, the contacts 218 and the lamp'L256 tobattery. The steady illumination of the lamp L256 indicates to theoperator at the operator position that a telephone call has beeninitiated on the combination alarm and telephone line associated withthe correcting circuit 245.

The operator at the operator position 60 answers the call by insertingthe plug P401 of the cord circuit in the operator position apparatus 400into the jack J251. When the plug P104 is inserted into the jack J251,an obvious circuit is completed at the contacts 255 of the jack'li- 251for energizing the winding of the control relay R230, thereby to causethe latter relay to operate. Upon operating, the control relay R2 50interrupts at the contacts 264 a point in the previously traced holdingcircuit for energizing the winding of the control relay R215, thereby tocause the latter relay to restore and interrupt at the contacts 216 thepreviously traced circuit for steadily illuminating the supervisory lampL256. Also, upon operating, the control relay R260 interrupts at thecontacts 262 a point in the previously traced circuit for energizing thewinding of the control relay R210, thereby to cause the latter relay torestore.

Also, when the plug P401 is inserted into the jack .1251, the repeatererator position apparatus 400 is operative associated with the repeater105 at the combination alarm and telephone station 50, assuming that thekey K420 has been operated away from its normal position. The circuitfor operatively associating the repeaters 410 and 105 extends fromground by way of the jack ring 248, the plug ring 242, C233, the plug122, G102, the contacts 116 of the alarm switch $115, the contacts 114of the door switch $113, the winding 101 ofthe repeater 105, thecontacts 112 of the hook switch S110, C101, the jack tip 121, the plugtip 238, C234, the plug tip 243, the jack tip 241, the jack ring 403,the contacts 408 of the ringing key K405 and the contacts 422 of the keyK420 to the lower terminal of the winding 414 of the repeater 410 andfrom ground by way of the jack tip 252, the plug tip 402, the contacts406 of the ringing key K405, and the contacts 421' of r the key K420 tothe upper terminal of the winding-413 of the repeater 412.

answers the call as previously described, the call may be extended toone of the telephone. substations as previously explained. In order toupon operating,

' eratively associated 410 included in the opring 231, the jack ring 3253, the plug ring After the operator at the operator position 60 extendthe call to one of the telephone stations, the key K415 is operated,thereby to cause the control relay R435 to operate as previously noted.Upon operating, the relay R435 completes at the contacts 438 aholdlng'circuit for energizing the upper winding thereof in series withthe winding of the answer relay R in the line circuit 180. Thelast-mentioned circuit extends from ground by way of the upper windingof the relay R435, the contacts 438, the plug sleeves 404, the jacksleeve 254, the jack sleeve 249, thepiug sleeve 241, C232, the plugsleeve 236,. the jack sleeve 123, C116 and the winding of R130 tobattery. Also, the control relay R435 completes at the contacts 431 aloop circuit for supplying battery current to the common batterytelephone instrument A at the combination alarm and telephone station50, this circuit extending from the grounded line conductor C102 of theline 100 by way of the contacts 116 of the alarm switch S115, thecontacts 111 of the hookswitchSllO, C104, the telephone instrument A,C103, C101,

the jack tip 121, theplug-tip 238, C234, the plug tip 243, the jack tip241, the jack ring 253, the plug ring 403, the contacts 408 of theringing key K405, the contacts 431 and the lower winding. of R426 tobattery. The extension of the connection over the telephone lineextending to the telephone substation, and the release of theestablished connection between the telephone substation and thecombination alarm and telephone station 50 are the same as thosepreviously explained.

Furthermore, it is noted that an alarm may be initiated on thecombination alarm and telephone line 100 at the combination alarm' andtelephone station 50 while the line 100 is opwith the correcting circuit245 as previously explained. At this time, the answer relay R130 and theimpulse relay R in the line circuit individually associated with thecombination alarm and telephone line 100 occupy their operatedpositions. Also,- when the answer relay R130 operates, it completes atthe contacts 136 an obvious circuit for energizing the control relayR100 in the line circuit 180, thereby .to cause the latter relay tooperate. Furthermore, the answer relay R130 interrupts at the contacts131 a point in a circuit, traced hereinafter, for energizing the windingof the control relay R in the line circuit 180. At this time, only thecontrol relay R265 in the correcting circuit 245 occupies its operatedposition.

' When the party at the combination alarm and telephone set 50 opens thedoor of the enclosing .casing thereat, the previously traced circuit foreffectively energizing the winding of the control relay R210 in thecorrecting circuit 245 is completed, thereby to' cause the latter relay'to operate and complete the previously traced circuit for energizingthewinding of the control relay R215. The control relay R215 thenoperates as previously explained. The party at the combination alarm:and telephone station. 50 then momentarily operates the alarm switchS115 as previously explained, thereby to interrupt at the contacts 116thereof the previously traced circuit for energizing the windingof thecontrol relay R210, whereupon the latter relay restores. Upon restoring,the. relay R210 completes, at the contacts 211, the previously mentionedcircuit for energizing the winding of the control relay R280,this'circuit extending from the grounded control conductor C293, by wayof Iii the contacts 27!, the contacts Zi'fi and the Winding of R286] tobattery. When energized over the above-traced circuit, the relay R288operates to complete at the contacts an obvious holding circuit forenergizing the winding thereof by way of the grounded control conductorC293 and interrupts at the contacts a point in the previously tracedcircuit for steadily illuminat ing the lamp L256. Also relay comlctes atthe contactsfiSt, a circuit for'intermittently illuminating thesupervisory lamp L256, this circuit extending from interrupted groundpotential appearing. upon the control conductor C25? by way of thecontacts the contacts E'idand the lamp L255; to battery. Tie flashing ofthe supervisory lamp L256 indicates to the operator at the operatorposition that the combination alarm and .c ephone line ativelyassociated with the correcting circuit 245 has an alarm conditionthereon. Also, upon. operating, the control relay R5283 interrupts at.the contacts 286- a point in the previously traced circuit forenergizing the winding of the answer relay R133 in the line circuit itsindiviclually associated with the combination alarm and telephone lineiilll, thereby to cause the latter relay to restore. Further, therelayR/lfiil prepares at the contacts 2% a point an alternative circuit,traced hereinafter, for en rgizing the winding of the answer relay RlZiland completes atthe, contacts 282 an obvious circuit for energizing thewinding of the control relay R293. Shortly after the winding of thecontrol relay R299 is energized over the previously mentioned circuit,this relay operates, as it is'of the slowto-operate type, and completesat the contacts 295 the previously mentioned alternative circuit forenergizing the winding of the answer relay R538. The last-mentionedcircuit extends from ground by way of the contacts the contacts 29L theresistor 244, the jack sleeve 2%, the plug sleeve 24!, C232, the plugsleeve the jack sleeve 123, CH6 andthe winding of R838 to battery. Whenenergized over the above-traced circuit, the answer relay- Riililreoperates.

From the foregoing it is apparent that, incident to the operation of thealarm switch Sl H5 at the combination alarm and telephone station 55,the correcting circuit operatively associated' with the alarm and.telephone line its causes the answer relay 'Rlfifi in the line circuitlflll to restore and then reoperate. When the answer relay Ri3llrestores, it completes at the contacts it? the previously for energizingthe Rlllll, this circuit winding the control relay extending from groundby way of the contacts i371, the contacts llll and.

the winding of EH35 to battery. When gized over the above-tracedcircuit, the EH35 operates to prepare at the contacts point in acircuit, traced hereinafter, for energizing the winding of the controlrelay Rita. When the answer relay reoperates, cornpletes, at thecontacts i553, the previously mentioned circuit for energizing thewinding of the control relay Rltil, this circuit extending from groundby way of the contacts itii, the contacts I92, the contacts 138, thewinding of Rial] and the resistor 32 3 to battery. when energized overthe above-traced circuit, the relay Riot? ope ates and completes at thecontacts lei the previously traced holding circuit for energizingwinding thereof. Furthermore, upon operating, the relay Rlfiil causesthe alarm recording equipment 383 to be operated, whereupon the recorderenerrelay Hill a mentioned circuit is operated to make a recordidentifying the combination alarm and telephone line I having an alarmcondition thereon as previously explained.

It is noted that the control relays Rl85 and Bi are or" theslow-to-release type. Accordingly, these relays remain operated duringthe time interval requir d for the answer relay R130 to restore andagain reoperate, due to the fact that this time interval is very short.Shortly after the answer relay REM reoperates, the control relay Blrestores as the circuit for energizing the winding thereof isinterrupted at the 93's, upon reoperation of the answer y Rllll. Uponrestoring, the control relay Ptltii interrupts at the contacts I86 thepreviously traced original circuit for energizing the winding thecontrol relay REG-ii. The operator at the operator position 6i] thenanswers the call by inserting the plug Pill! of the cord circuit in theoperator position apparatus 408 into the jack. JEN as previouslyexplained. When the plug is inserted into the jack J25I, the previouslytraced circuit for energizing the winding of the control relay R2533 iscompleted, thereby to cause the last-mentioned relay to operate andremove ground potential from the conductor When ground potential isremoved from the control conductor C293, the previously traced holdingcircuits for energizing the windings of the control relays Elland R255are interrupted, thereby. to cause the latter relays to Upon restoring,the control relay R280 recomp le-tee at the contacts 266 the originalcircuit for energizing the winding of the answer relay thereby toprevent the last-mentioned relay from restoring at this time. Also, uponrestoring, t..e control relay R280 interrupts, at the contacts thepreviously mentioned circuit for energizing the winding of the controlrelayRlQil, thereby to cause the latter relay to restore. Uponrestoring, the control relay R2l5 interrupts the contacts 218 thepreviously traced cii uit for illuminating the supervisory lamp Lil Inorder to release the established connection between the combinationalarm and telephone station 5!? and the operator position as, theoperator thereat withdraws the plug Paul from the jack J25! aspreviously explained.

It is noted that, when the combination alarm and telephone line 5953 hasbeen cleared of faults, the connection between this line and thecorrecting circuit ti t-E5 is interrupted by withdrawing the plugs andPhil? of the patching cord 23! from the respective jacks J 520 and JMS.When the plug is withdrawn from the jack J l 20, the previously tracedcircuit for energizing the i ding of the answer relay RISE isinterrupted, thereby to cause the latter relay to restore. Uponestoring, the answer relay R539 completes at e contacts 63? thepreviously traced circuit or energizing the winding of the control relaythereby to cause the latter relay to operate while the control relayRiQ'd occupies its operated position. Shortly thereafter, the controlrelay restores and interrupts at the contacts till the previously tracedcircuit for energizing the winding of the control relay EH55, whereuponthe last-mentioned relay restores shortly thereafter. Accordingly, theremoval of the P235 from the jack J12!) does not cause the control relayRite in the line circuit I80 to operate atthis time.

.In; the foregoing. description of the operation of the'co-rrectingcircuit 245 in conjunction with thedefective combination alarm andtelephoneline I00, the'plug P240 of the patching,

cord 23! was inserted into the jack J246 due l to the fact that it wasassumed that the ne'ga- I tive lin'e conductor C102 of the line llliihad a ground fault thereon. In the event the positive linecon'duotor'Clill of the combination alarm and telephone line Hill had a groundfault thereon, the plug P240, of the patching cord 23! would theoperations .of the correcting'circuit 245 in conjunction with thecombination alarm and telephone line 100 under these conditions areomitted.

iwhilethere has been described what is at present considered to be thepreferred embodiment of the invention, it will be understoodthat variousmodifications may be made therein', and-i it isintended to cover in theappended-claims all such' odificationsas fall within the spirit and;scope of the invention. I

What is claimed isr Y 1'; In a telephone system, a station provided withan enclosing casing having a door, a line the H tending to said stationand connected to a source f 'of current-telephone apparatus housed insaid casing, a" resistor 'atsaid station, said telephoneapparatusandsaid resistor being normally con? nected in series circuitrelationship in said line,

the resistance of saidresistor'being'so propor-" tioned that saidtelephone apparatus is normally effectively 'deenergi'zed; a switch atsaid station operativeto reduce the effective resistance of saidresistor, thereby efieotively to energize said telephone apparatus,means controlled when the efiective resistance of said {resistor isreduced "for initiating a telephone call on said line, and meanscontrolled by the door 'of "said casing forfoper atin'g said switch. i

, 2. In a telephone system; a station provided with an enclosing casinghaving a door, a line extending to said station and connected to asource of current, a repeater and a resistor at said station, saidrepeater and said resistor being,nor-' mally connected in series circuitrelationship .in said line, the resistance'ofsaid resistor being soproportioned that said repeater is normally effectivelydeenergized, atelephone instrument housed in said; casing and toperativelyfassociatedwith said repeater,='a"switch at said station operativeto'-short-circui't said resistor, thereby effectively to energize saidrepeatenmeanscontrolled when j said resistor is 'short-circuited forinitiating a telephone call on said line, and means controlled by thedoor of said casing for operating said a switch. i i v 3 In a telephonesystem, a station provided with an enclosing casing having a door, aline extending to said station and connected to a source of current, arepeater at said station normallyoperatively disassociated from saidline, a first telephone instrument of th'esound-powered type housed insaid casing and operatively associated with said repeater, asecondtelephone instrument of the common battery type housed in saidcasing and normally operatively disassociated from true ' mitting a saidlin e, means controlled by the door of said casing for operativelyassociating said repeater with said line, means including a hook switchhoused in said casingfor operatively associating said second telephoneinstrument with said line,

and means controlled when said repeater or said second telephoneinstrument is operatively associated with said line for initiating atelephone call on said line.

i. In a telephone system, a station provided" with an enclosing casinghaving a door, a line ex tending to said stationan'd connected to asource of current, a repeaterat'said station 'provi'ded with firstandsecond windings, a first telephone instrument of thesound-poweredtype housed in said casing and loperatively associated withthe first windingof said. repeater, the second winding of said 'iepeaterbeing normally operatively dis- 'associated from said line, a secondtelephone instr'ument of thecommonlbattery typehoused in said casingandnormally'operatively disassooiated from said line, means controlledwhen the door of said casing is opened for operatively associatingthesecond winding/of said repeater with said line, 'means including'ahookswitch housed in 1 said casing and" operative to short-circuit thesecond winding of said repeater and operatively to associate said secondtelephone instrument with said line, and means controlled when thesecond" winding of said repeater or said second telephone instrument is'operatively associated with said line for initiating a telephone callonsaid line.- -5;Inasignalingsystem, a station, an operator position,aline extendingbetween said station and said operator position andconnected to a source or current, telephone apparatus at said stationand adapted-tobe'operati'vely associated with said line, answeringapparatus'at said operator position jandadapted to be operatively'associated'with said linie, a line'cir'cuit associated with said lineandincluding' first and second relays, a resistor at said" station,said-first'relay, said second relay" and'saidresistor being connected inseries circuit relationship jinsaid, line, said first relay beingnormally operated and said second relay being normallyrestored, means atsaid station for reducingthe effectiveresistance of said resistor,

therebyto cause said "second relay to operate,

I'neansat said station for. interrupting said line,

thereby to cause said first relay to restore, means responsive-to therestorationof said first relay orthe operation ofsaid second relay fortrans I first-signal to said operator position,

and means responsive to the restoration of said first relay'followingthe operation of said second relay for transmitting'a second signaltosaid operator position.

6, Ina telephone. system, a station provided"- with an enclosing casinghaving a door, a line extending to saidstation and connected to a sourceof'current; telephone apparatushoused in said casing'and adapt'edto-b'eoperatively associated wit said line, answering apparatus at saidoperator position andadapted to be operatively associated with saidline', 'a line circuitassociated-with said line and including first andsecond relays,

ares istor at said station, said first relay, said sec' 0nd relay andsaid resistor being connected in series circuit relationship in saidline, said first relaybeing normallyoperated and said' second relaybeing normally restored, means controlled by' the door of said casingfor reducingthe efiective resistance ofsaid resiston-thereby to causesaid 'second relayto operate, 'means including a device housed in saidcasing for'interru'pting said line, thereby to cause said first relay torestore, means responsive to the restoration of said. first relay or theoperation of said second relay for transmitting a first signal to saidoperator position, and means responsive to the restoration of said firstrelay following the operation of said second relay for transmitting asecond'signal to said operator position.

'7. In a signaling system, a station, an operator position, a lineextending between said station and said operator position and connectedto a source of currentytelephone apparatus at said station and adaptedto be operatively associated with said line, answering apparatus at saidoperator position and adapted to be operatively as sociated with saidline, a line circuit associated withsaid line and including first and,second relays, a resistor at said station, said first relay, said secondrelay and said resistor being connected in series circuit relationshipin said line, said first relay being .normally operated and said secondrelay being normally restored, means at said'station for reducing theeffective resistance of said resistor, thereby to cause said secondrelay to operate, means at'said station for interrupting said line,thereby to cause said'first relay to restore, means responsive to theoperation.

of said second relay for initiating a telephone call on said line, andmeans responsive to the restoration of said first relay following theoperation of said second relay for initiating an alarm on'said line.

8. In a signaling system, a station, an operator position, a lineextending between said station and said operator position, said linebeing subjected to ground faults, telephone apparatus at said stationan'd'adapted to be operatively associated with said line, means at saidstation for initiating a telephone call on said line, means at saidstation for initiating an alarm on said line,-

a line circuit normally associated with'said line,

a correcting circuit adapted to be associatedwith said line when saidline has a ground fault there'- on, means controlled: from said operatorposition for disassociatingsaid line circuit from said line and forassociating said correcting circuit withsaid line, means includedin-each of said circuits and responsive to thepresence' of a telephonecall on said line when the circuit is associated therewith fortransmitting a first signal to said operator position, and meansincluded in each of said circuits and responsive to the presenceof analarm on said line when the circuit is associated therewith fortransmitting a second signal to said operator position.

9. In a signaling system, a station, an operator position, a lineextending between said station and said operator position, saidlinebeing subjected to ground faults, telephone apparatus at said stationand adapted to beoperatively associated; with said line, means at saidstation for initiating a telephone call on said line, means at saidstation for initiating an. alarmon said line, a line circuit normallyassociated with said line, a correcting circuit adapted to be associatedwith said line when said line has aground fault there'- on, meanscontrolled from said operator position for disassociating said linecircuit from said line and for associating said correcting circuit withi said line, means included in each of said circuits and responsive tothe presence of a telephone call on said line when the circuit isassociated thereline, and means includedin each of said circuits and.responsive to the presence of analarm on" at said station for initiatingan alarm on said line, a line circuit normally associated with saidline, a correcting circuit adapted to be associated with said line whensaid line'has a ground fault thereon, means controlled from saidoperator position for disassociating said line circuit from said. lineand for associating said correcting circuit with said line, a relay,means included in each of said circuits and responsive to the presenceof an alarm on said line when the circuit is associated therewith forcontrolling the operation of said relay, means operative toidentifysaidline, and means including said relay for controlling the operationof said last-mentioned means. i r

111. In'a signaling system, a station provided with an enclosing casinghaving a door, an

operator position; a line extending, between said' station and saidoperator position, said, line being'subjected' to groundfaults,'telephone apparatus housed in said casing and adapted to be'operatively associated with said line, a device housed in said casing,a line circuit normally I associated with said line, a correctingcircuit adapted to be associated with said line when said line has aground fault thereon, means controlled from said operator position fordisassociating said line circuit from said line and for associating saidcorrecting circuit with said line, a relay,

means included in each of said circuitsand responsive to the opening ofthe door ofsaid casing and thesubsequent operation of'said device whenthe circuitis associated with said line for controlling the operation ofsaid relay, means operative to identify said line, and means includingsaid relay for controlling the operation of said lastrmentioned' means.v

12. In a signaling system, a station provided with an enclosing casinghaving'a door, an operator position, a line extending between saidstation and said operator position, said line being subjected to ground.faults, telephone apparatus housed in said casing and adapted to 'beoperatively associated with'saidline, a device housed insaid: casing, aline circuit normally associated with said line, a correcting circuitadapted to be 7 associated with said line when said line has a groundfault thereon, means controlled from said operator position fordisassociatingsaid line circuit from said-line and for associating saidcorrooting circuit with said line; a relay individual vto said line,means included in each of said circuits and responsive to the opening ofthe door of said casing and the subsequent operation of said devicewhen. the circuit is associated with said line for causing: said relayto operate, means operative to identify said line, and means responsiveto the operation of said relay for marking said line'to be identifiedand for controlling the operation of said last-mentioned means.

CLARENCE E. LOMAX. CHARLES F; F'FOLLIO'I'T.

